The present invention relates to a range switching device which is mounted on a vehicle. More particularly, the present invention relates to a range switching device (a so-called shift-by-wire system) for controlling a motor according to a drive range (e.g., P, R, N, D) selected by operation of a shift range selecting portion such as a shift lever, and operating a shift range operating portion such as a manual valve and a parking gear mechanism through a range control shaft to switch a shift range.
Description of the Related Art
A range switching device of a so-called shift-by-wire system has been proposed recently for switching a shift range by a motor. This range switching device operates as follows: driving force of the motor controlled according to operation of a shift lever is transmitted to a range control shaft through a driving portion, thereby pivoting the range control shaft. A hydraulic control device and a parking gear mechanism of an automatic transmission are then operated through a detent lever fixed to the range control shaft. The range switching device thus switches a shift range. A range position detection sensor as a detecting portion detects the pivot position of the detent lever, that is, the pivot position of the range control shaft. The range switching device thus controls the shift-range switching operation while detecting the range switching state.
In the range switching device, the range control shaft extends through the detecting portion and an arm member is fixed to one end of the range control shaft. In order to obtain a watertight state inside a case member, a waterproof structure is implemented by a sealant disposed between the range control shaft and the detecting portion. In this structure, however, water may enter the case through the range control shaft, and the waterproof effect is not sufficient. Improvement has therefore been desired.
A range switching device which includes an output shaft rotatably supported by a front housing as a case member and connected to a control rod as a range control shaft has been proposed (e.g., see Japanese Patent Application Publication No. 2007-56961). In this range switching device, the output shaft has spline grooves and the control rod has spline teeth so that the output shaft and the control rod are spline-fitted to each other.